Massively, yes. We could start seriously betting on real-world events. It becomes harder to make crappy predictions ("If this bill isn't passed, crime will skyrocket!") when people can just check the going odds.

ETA: Much better explanation: http://squid314.livejournal.com/352406.html

Interesting.

Does something like that exist in other countries?

We've got this in Australia: http://www.sportsbet.com.au/betting/current-affairs But it's no-where near the level that article describes.

I worked next to the guys from Smarkets (https://smarkets.com) for a while. It looks like they're focussing heavily on sports betting now, but they'll do politics or media things when there's interest.

set up your own bitcoin betting site and host it in antigua

Not for us, apparently.